Electrical Transformers Operation, Testing and Maintenance

Objectives

The course is intended to provide electric engineers with collective and recent knowledge about transformers including ordering specifications, commissioning, operation, analysis, maintenance, testing and protection. The information includes both theoretical and practical aspects and will be enhanced with computer software in appropriate sections.

Course Program:

General Background and Recent Advances

• Principles of operation
• Types and construction
• Rating of transformers
• Standard specification
• Ordering, transportation and installation
• Insulation and magnetic materials
• Progress of transformer technology

Construction and Analysis

• Phasor diagram and computer simulation
• Core losses and efficiency
• Transient analysis
• Harmonic analysis
• Types of winding
• Transformer tanks and cooling systems
• Transformer oil
• Transformer connection

Operation and Maintenance

• Tap-change and voltage control
• Loading of Power transformers
• Parallel operation
• Unbalanced operation
• Maintenance and trouble shooting
• Maintenance of unattended transformers
• Filtering of oil, filling of oil and dry-out
• Fault detection
• Rewinding
• Partial discharges and their location

Protection and Testing

• Types of protection
• Choice of protection
• Safety devices and fitments
• On-line fault diagnosis
• Testing

• 1. 1. • Acceptance tests
        • Commissioning tests
        • Routine tests
        • Special tests

Practical Applications problems and special transformers

• False tripping and magnetizing inrush currents
• Transient voltage and voltage surges
• Neutral grounding, arc suppression coil and tertiary winding
• Audible noise and noise reduction
• Guides for loading transformers
• Short circuit forces and mechanical stresses
• Special transformers: Autotransformer, Phase shift transformer,
• neutral grounding transformer, Arc-furnace transformer, Induction
• furnace transformers and other special transformers
• Open forum to discuss some practical problems raised by attendants